Method of and apparatus for forming metal tubes.



A. W. GILLESPIE.

METHOD or AND APPARATUS rou TORMTNG METAL TUBES.

APPLICATION FILED OCT. 30. 1914.

Patented Jan. 5, 1915.

A. W. GILLBSPIE.

METHOD OF AND APPARATUS FOR PORMING METAL TUBES.

APPLICATION FILED 00T. so, 1914.

1,124,221., Patented Jau, 1915.

2 SHEETS-SHEET 2.

Hmm.. A'

M. "9". www?,

' sTii-Tns PATENT vOrgien ALEXANDERV W.: eI'LLEsPIE, or cHIcAGo HEIGHTS.A ILLINOIS, AsSIGNoa To cALUI/IET ,.sTEEL COMPANY, or cHIcAeo, ILLINOIS, A coRronATIoN or ILLINoIs.

METHOJDl E AND APPARATUS lEOE EORMING METAL TUBES. i

To all whom 'it mag/concern.' l

Be it known thatI, ALEXANDER W. (in. LEsrIE, ai citizen of the United States, residing in Chicago Heights, in the county of Cook and State of illinois, have invented anew and useful Improvement 1n Methods of and Apparatus for Forming Metal Tubes, ofwhich the following is a specication.

'My invention relates in general to tube forming apparatus and more particularly to -method of forming 'metal tubes frommat stripsv of metal having the length -of the tube desired andthe width equal substam tially to. its' circumference, the tube being formed of such strip by bending thelongi- ,tudinal edges of said tubezuntil they abut one against the other inv a finished cylindrical tube and to apparatus particularly' adapted to the practice ofsuch method...v am aware that numerous forms of ap- 85 sive portions of it on. a relatively wide curve and then gradually bending it more until `the longitudinal edges abut oneagainst the other in the iinished tube. 'T his -gives the molecular structure time to adJust itself and i more eifectively withstand the bending strain, relieving` in large part strain upon the apparatus and reducing also materially the danger of fracturing the. material or cracking its outer surface, n yto the fullest extent the native strength lof the sheet when in iiat conditionbefore bend- A further object of the .invention 1S .the provision of effective guiding means w1th- B0 in the former or Vdie for preventing twist-J ing of the tubes. I

A still further object is a general improvement in the designv and efliciency of such aratus.

a y .l p ther objects and advantages.) the 1n- Specication of Letters Patent.

besides retaining Patented Jan. 5, 1915.

' AApplication led October 30, 1914. i Serial No. 869,358.. i

"ventionwill be apparent as it is better understood from the following description when considered in connection with the accompanying drawing illustrating a preferred embodiment thereof.

' Referring to the drawings: Figure 1 is a sectional view taken centrally through an apparatus embodying my invention, parts top plan view of the bottommember of the form; Fig. 4 1s a bottom plan view of the top Vmember of the form; Fig. 5 is a section taken substantially on the' line 5-5 of Fig. llgFig. 6 is a section taken substantially on the line 6--6 of Fig. 1;.Fig. 7 is a perspective view ofva-skelp partially formed into a ftube andshowingthe manner of bending;

and Figs. 8, 9 and 10 are diagrammatic views showing the changes wrought in the curvature v of the material as it passes through the former.

My present invention concerns itself principally with a die or former adapted to receive a .somewhat slightly bent piece of skelp vat one end and to turn out a substantially completedtube at the other. This former is Igenerally indicated at 11 in Fig.` 1, in which vlew 1s indicated also a pair of, feeding-in rolls 12 and-13 and a pair ofdelivery and finishing rolls 14 and 15. These rolls are mounted in a suitable vframe or Supports which, for thesake of'clearness, have been omitted from the drawing and which need not be described herein. Y

The former in the present embodiment of vthe invention now to bel described consists of a bottom or female member 16 and a twopart top member indicated at 17 and 18.

which, notably the feeding and delivery rolls, Aare merelyindicated; Fig. 2 is a top plan vlew of the same with the upper feeding and delivery -rolls removed; Fig. 3 is a be engaged by suitable supports. The forward end of this member istapered as seen yat 21 to extend between the rolls 12`and 13 at the sides. A slit 22 is provided centrally -of the former and in this slit rests one end 23 of a separating wedge 24, the forward edge of which. 2 5 rides just. above the lower feed'roll 13. A channel. 26 is lformed between the top and bottom members ofv the former and extends longitudinally therethrough. The forward end -of this channel is'disposedvatthe'feeding end between they 110 rolls 12 and 13, the forward end of the chan# nel being formed between the plug or wedge 24: and a movable stripper 26 having a curved outer face 27 adapted to ride on the face of the feeding roll 12'. The stripper 26 is secured upon a rocking bar 28 having a recess 29 therein in which is engaged a lug "3l upon the upper face of the forward part 17 of the top member. A spring 32 holds the stripper 26 in contact with the roll l2 and causes it to effectively separate the entering skelp from the upper roll. T he feeding-in rolls 12 and 13 are formed to produce a slightly bent slrelp, the form of which is substantially that shown in Fig. 10. 1f necessary other rolls may be provided to aid in producing this form.

The channel 26 is curved in all its portions and narrowing or reducing toward its delivery end. rl`he bottom and top portions of the skelp in passing through it are curved to substantially but not accurately semi-circular form and particularly toward the delivery end these portions are connected by intermediate side curves, giving the tube, as it leaves the former, a slightly elliptical or oval shape, as is seen in lfig. 8, it being intended that the finishing rolls will force the tube into perfect cylindrical form. Figs. 8, 9 and l0 indicate the shape given a single portion of the skelp as it passes dierent points in the die. While these portions are all nearly circular, they are ofi' of a circle sufficiently to permit the oval shape shown in Fig. 8 to be gradually produced. All points, however, of each of the sections shown and of intermediate sections, which might be taken are curved on the arcs of circles, several arcs being employed at each successive point in the channel. At the feeding end the centers and radii of these arcs are so nearly the same as to be hardly distinguishable. At the delivery end, however, the difference in radii of these arcs is somewhat more apparent, those of the arcs at the side being greater than those of the arcs forming the top and bottom. This continuous and gradual bending is perhaps best appreciated by viewing Fig. 7, in which is shown a piece of skelp 33 from which it will be noted that there is no sudden bending of the material at any point.

On the two parts of the top member and extending downwardly into the channel formed by it with the bottom member is a longitudinally extending rib 34 which is substantially co-extensive with the former, this rib decreasing in thickness as is demanded by the approaching edges of the slzelp. The rib 34 serves to prevent twisting of the skelp in the former and insures that the adjoining edges meet in a substantially straight line. The bottom member is slit,from the delivery end inwardly, as seen at 35, to permit it to be adjusted to take up wear. The two parts of the top member contact at beveled surfaces 36, a wedge 37 being provided to engage a lug 38 on the part of the top member having upper surfaces 3() and enga ging under lips QeXtending upwardly from the bottom member to hold the parts firmly together in service. A perfect Icylindrical shape is giventhe tube by the finishing rolls. 1t will be understood that the word elliptical as used herein includes oval or equivalent shapes.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing without further description, and it will be obvious that varous changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing any of its material advantages, the form hereinbefore described bein merely a preferred embodiment thereo 1 claim:

l. 1n an apparatus for forming metal tubes, in combination: means for curving a flat piece of skelp first on arcs of large circles continuous from side to side of the skelp and gradually reducing the radii of said curve until said skelp is elliptical in cross section with its edges substantially in contact; and means for reducing the radii of the longer curves of said elliptical form to produce a circle, in cross section.

2. In an apparatus for forming metal tubes, in combination: means for curving a flat piece of skelp rst on arcs of large circles continuous from side to side of the skelp and gradually reducing the radii of said curves until said slrelp is elliptical in.' cross section with its edges substantially in contact; and finishing rolls for reducing the radii of the longer curves of said elliptical form to produce a circle, in cross section.

3. In an apparatus for forming metal tubes, in combination: forming rolls and a former having a channel, for curving a flat piece of skelp first on arcs of large'circles continuous from side to side of the skelp and gradually reducing the radii of said curves until said skelp is elliptical in cross section with its edges substantially in contact; and means for reducing the lradii of the longer curves of said elliptical form to produce a circle, in cross section.

4. In an apparatus for forming metal tubes, the combination of feeding rolls and delivery rolls, and a former positioned between said feeding and said delivery rolls, said former comprising a member having a channel extending longitudinally thereof .versely to curve a flat piece of skelp rst on arcs of large circles continuous from side to side of the skelp, and gradually reducing the radii of said curves until said -skelp is.

elliptical'in cross section with its edges substantially in contact, and said delivery rolls being shaped to reduce the radii of the longer curves of said elliptical form to produce a circle in cross section.

5. The method of forming metal tubes which consists in curving a Hat piece of skelp, first on arcs of large circles continuous from side to side of the skelp, and gradui 

